Automatic assembly machine



July 6, 1965 L. c. TULLIS AUTOMATIC ASSEMBLY MACHINE 5 Sheets-Sheet 1Filed Sept. 3, 1963 INVENTOR. Z 221 C. 701.05 B flair-us 9' 5142-11:

Afforngzs AUTOMATIC ASSEMBLY MACHINE 7 Filed Sept. 3, 1963 5Sheets-Sheet 2 m Q h q LHHT I r i INVENTOR.

Lraz. CZ 77.0.1.1: BY

y 6, 1955 L. c. 'TULLIS 3,192,873

y 1965 c. TULLIS 3,192,873

' AUTOMATIC ASSEMBLY MACHINE Filed Sept. 3, 1963 5 Sheets-Sheet sINVENTOR. Lye-u C. Flu/s July 6, 1965 c. TULLIS 3,

I AUTOMATIC ASSEMBLY MACHINE Filed Sept. 3. 1963 5 Sheets-Sheet 4 Wk ,l

060: 9' $1001? After/re s y 1965 1.. c.1'u| 1s 3,192,873

AUTOMATIC ASSEMBLY MACHINE Filed Sept. 3, 1963 5 Sheets-Sheet 5INVENTOR. Ln'u. C. 7Z/1.us

United States A Patent M r 3,192,873 AUTQMAIIC ASSEMBLY MAC Lyeli C.Tuliis, Janesville, Wis, assiguor to Gilman Engineering 8: Mtg. (30.,Inc, .ianesvilie, Wis., a corporation of Wisconsin Filed ept. 3, 1963,Ser. No. 386,386 19 Ciaims. ((Il. 104-162) This invention relates to anautomatic assembly machine of the type adapted to assemble variousmechanical or electrical components and in which a series of sepa rateplatens each carrying a work assemblage are moved intermittently fromstation to station along an assembly line with automatic placement ofwork parts at the different stations as each platen moves down the lineand a return of empty platens from the end of the line after thecompleted work assemblage is removed from successive platens.

In the manufacture of suchmachines, it is desirable to provide aconstruction which may be adapted for various products and therebysubstantially reduce the cost as compared to specifically designedmachines for each prodnet.

The present invention accomplishes this by providing a construction ofunit length having a basic number of stations and which may be readilyadded to in length to provide additional stations merely by addingunits.

In order to provide a basic construction which may be made for variousassembly needs, a simple way of providing changes in the desired speedand the dwell periods for the work carrying platens is employed in themachine. Also it is possible to vary the length of the sta tions with acorresponding change in distance of travel of the platens from stationto station to accommodate work of different sizes.

The inertia forces in transferring the platens from station to stationare taken care of by the use of a Scotch yoke drive, and by theelimination of backlash between the parts of the drive.

The need for greater access to the work on the platens is provided byuse of a simple transfer mechanism for the fixtures or platens, leavingthe top of the latter free for access from both sides and from above andalso providing access from the bottom if needed. 7

The platens move on an assembly track and are indexed at each stationfor Work thereon, and are returned empty on a track beneath the assemblytrack. In order to eliminate interference with the transfer mechanism bythe returning platens, the platens are turned over at each end of thetracks by a turnover mechanism which provides for free manual removal ofany platen at the end of the line and replacement thereof.

Any suitable mechanism for applying parts to the work, securing theparts in place and checking as to fit or completeness of the assemblageat various stations and stages of assembly may be employed, and thepresent invention is not concerned with these other than to provideadequate access for these to the work. r

The present invention is more concerned with the work transporting andindexing mechanisms which constitutes the basic machine, including theclosed circuit step by step movement of the platens.

The accompanying drawings illustrate the best mode contemplated ofcarrying out the invention.

A In the drawings:

FIGURE 1 is a perspective view from the back with parts broken away ofan automatic assembly machine showing the basic elements fortransporting and indexing the work platens, and without showing theplatens and the several mechanisms at the various stations for effectingthe work;

FIG. 2 is a top plan view of the basic machine of FIG.

' actuates a lever 13 pivotally mounted on the correspond 7 3,192,873Patented July 6, 1965 1 with the machine broken in length to avoidunnecessary duplication and with the platens in place;

FIG. 3 is a front side elevation of the machine of FIGS. 1 and 2, brokenin length as in FIG. 2;

FIG. 4 is an enlarged transverse section through the machine takengenerally on line 44 of FIG. 2;

FIG. 5 is an enlarged detail section showing the drive for the transportcage;

FIG. 6 is a detail view showing part of the drive of FIG..5 in theopposite operating position;

FIG. 7 is a detail section taken on'line 77 of FIG. 5;

FIG. 8 is an enlarged detail end view of the drive for the turnovermechanism;

FIG. 9 is a view similar to FIG. 8 showing the parts in an oppositeoperating position;

FIG. 10 is a detail view taken on line lit-10 of FIG. 8;

FIG. 11 is a detail view of the detent locking means for the platens onthe turnover mechanism, taken on line ll1l of FIGS; and

FIG. 12 is a detail schematic view of an alternative form of shot pinactuation and which also may be employed in actuating assembly mechanismat the several stations. I

The machine illustrated has a supporting base 1 adapted to rest on thefloor and extending for the full width and length of'the machine.

The base 1 has a plurality of longitudinally spaced pairs of oppositelydisposed upstanding side posts 2 upon which the several operatingelements are carried. Intermediate posts 3 are adjustably positioned toprovide sup port for the platen indexing mechanism to be describedhereinafter. Additional posts, not shown, may be secured to the base tocarry various operating mechanisms used in assembling the workpieces atselected stations.

The side posts 2 extend outwardly from base 1 to provide an efiectiveincreased width for the machine and better stabilize its support uponthe floor. The outward lateral extension of the side posts 2 ,on thebackside of the machine shown-in FIG. 1 carry a cam shaft 4 extending'for the length of the machine. V

The side posts 2 additionally carry two sets of tracks, the upper setcomprising opposed laterally spaced channel rails 5 extending for theoperative lengthof the machine, and the lower set comprising a similarpair of opposed laterally spaced channel rails 6 generally coextensivewith tracks 5. The'tracks 5 and 6 are horizontal and parallel so thatthey are unifcrmly spaced throughout the length of the machine. e

A plurality of separate work carrying platens 7 are disposed between therails of each set of tracks 5 and 6 to be moved therealong in successionfrom station to station. For this purpose each platen '7 has a pair oflaterally extending trunnion carried rollers 8 on each side and whichride in the groove ofthe correspondingchannel rail and support theplaten.

The platens 7 are generallyspaced end to end and are I individually shotpinned at each successive station to hold them in position forperformance of work assembly 'operations thereon at the correspondingstations. Each platen 7 is adapted to receive work parts (not'shown) atsuccessive stations and by the'time it reaches the end of ing post 3 at14 and which pivotally carries a link 15 extending upwardly to an arm 16secured to the rocker shaft 10.

The rocker shaft has an arm 17 fixed thereto at each station and whichextends inwardly to a position beneath the platen 7 as illustrated inFIG. 4. A shot pin -18 is pivoted to the inner end of arm 17 and extendsupwardly through a vertical guide member 19 secured to the adjacent railof the upper tracks 5. The. upper end of each shot pin 18 is adapted toenter a recess 20 in the corresponding platen 7 at the given station.

Each shot pin 18 is spring loaded by a suitable spring 21 disposed tobias pin 18 upwardly into the recess 20. A safety relief device isdisposed in link and provides for emergency shortening of the link incase of jamming of the shot pin in recess 20. For this purpose the link15 is made in two sections and has incorporated therein between thesections an air cylinder 22 secured to one end section thereof and apiston 23 secured to the opposite end section thereof and adapted tooperate in the cylinder 22. Since the leverage system between camfollower 12 and shot pin 18 is arranged to Withdraw the pin as follower12 is raised by the cam 11, and to drive the pin into the recess upon alowering of follower 12, the piston 23 is normally biased by airpressure in cylinder 22 in the direction of greatest length for the link15 so that in the event the shot pin 18 sticks in recess 29 the raisingof the follower 12 by cam 11 will effect a shortening of the link by theyielding movement of the piston within the cylinder. In the event ofjamming that might prevent shot pin 18 from entering recess 20 by theaction of spring 21 as the cam 11 drops away from cam follower 12, thelatter will remain out of contact with cam 11.

The cams 11 on cam shaft 4 are designed to permit followers 12 to dropwhen the platens have been advanced to their corresponding stations sothat the several shot pins 18 move upwardly into the correspondingrecesses under the influence of the springs 21. The platens 7 arethereby indexed or locked at their respective stations while work isperformed upon the work assemblies thereon.

When it is time to advance the platens again, the earns 11 are designedto lift the followers 12, thereby rocking shaft 10 in a directionwithdrawing the shot pins 18 from their recesses 20 against springs 21.

Should it be desired to provide for positive movement of shot pin 18into the platen recess 20 when cam 11 raises and lifts follower 12, aconstruction similar to that shown in FIG. 12 may be employed.

In the construction of FIG. 12 the'fulcrum 14 for the lever 13 isdisposed intermediate the follower 12 and the connection for the link 15so that as follower 12 is lifted by cam 11 the shot pin 18 will be movedupwardly into recess 20 in the corresponding platen 7. Should themovement be jammed for any reason the safety device in link 15 willyield to provide a lengthening of the link. The normal arrangement ofthe cylinder 22 and piston 23 should provide for this as shown;

Also in the construction of FIG. 12 a fluid pressure cylinder 24constantly biases the cam follower 12 against cam 11 and effects awithdrawal of the shot pin 18 from recess 20 when cam 11 drops away fromthe follower 12.

For the purpose of freeing the shot pins 18 so that they can bemaintained out of recesses 20 if desired, the piston 23 in cylinder 22may be double acting so that the fluid operating pressure in thecylinder may be reversed thereby lifting follower 12 free from theinfluence of cam 11 and holding the pin 18 in its retracted position.

A drive motor 25 is mounted on the back of the machine and drives thesame through a primary belt 26 to an electric clutch and brake unit 27and from thence by belt 28 to a cross shaft 29 extending transversely ofthe machine base.

A suitable zero backlash worm gear speed reducer 30 drives cam shaft 4from the cross shaft 29.

The cross shaft 29 extends to the front side of the machine, as shown inFIGS. 2-4 and drives a cam shaft 31 extending parallel to shaft 4 forthe lentgh of the machine, by means of a second zero backlash gearreducing drive 32.

The cross shaft 29 also drives the transfer drive mechanism 33 on thefront side of the machine by means of the toothed timing belt-s 34 and35 and countershaft 36. The lower belt 34 drives the countershaft 36from cross shaft 29. The upper belt 35 drives the clutch shaft 37 oftransfer drive mechanism 33 from countershaft 36. By interchanging thetoothed pulleys over which the belts 34 and 35 train in variouscombinations, it is possible to provide different transfer speeds forthe platens 7 for different work cycles. This is readily possible sincethe several pulleys are secured on the outer ends of the correspondingparallel shafts 29, 36 and 37.

The transfer drive mechanism 33 comprises the clutch 38 connecting theinput and output end sections of shaft 37, a crank 39 on the output endof shaft 37, a Scotch yoke 40 disposed to be driven by crank 39 and apair of transfer bars 41 and 42 driven by the Scotch yoke. A suitablegear reducer 43, which is preferably of the zero backlash type, may beprovided between sections of the input shaft 37, as may be desired.

The clutch 38 may be of any suitable type, the one illustrated in FIG. 4being a dog clutch with its input member 44 secured to the inner end ofthe input part of shaft 37, and with an axially shiftable member 45rotationally interlocked to the output section of shaft 37.

When the shift member 45 is moved axially into interlocking engagementwith the constantly rotating member 44, the output section of shaft 37will rotate to drive crank 39. When the shift member 45 is moved axiallyaway from member 44, the clutch is opened to disconnect the drive tocrank 39.

The crank 39 has a roller 46 carried thereby and riding in the verticalchannel 47 of Scotch yoke 40 so that as crank 39 rotates from onehorizontal position through 180 to the opposite horizontal position itmoves the Scotch yoke 40 a distance longitudinally of the machinecorresponding to the diameter of the circular path of movement of roller46. This distance of movement of the Scotch yoke corresponds to thedistance of movement required for a platen 7 in moving from one stationto the next.

The machine is adjustable to accommodate different length stations anddifferent numbers of stations. The machine illustrated, for instance, isconstructed in six foot unit lengths with the drive mechanism located atonly one of the units, and with a selected number of units to providethe desired number of stations, there being six stations for each unit,and each station having a length of one foot. In such a construction,the platens 7 are generally less than one foot in length and they travelone foot in moving from one station to the next.

Where it is necessary to provide longer stations, it is possible tospace the platens so that there are only four stations per unit lengthof six feet with each platen traveling eighteen inches from station tostation, or three stations per unit length with each platen travelingapproximately two feet from station to station.

a To accommodate this adjustment of the machine, the crank 39 has threespaced openings 48, 49 and in its length for selectively receiving thetrunnion support for roller 46. When the roller 46 is located at opening48 in crank 39 as shown, the reciprocal stroke for the Scotch yoke .40is approximately one foot in the machine referred to above asillustrative. When the roller 46 is at the intermediate opening 49 incrank 39, the throw of the Scotch yoke 40 is approximately eighteeninches, and when the roller 46 is at the outer opening 50 in crank 39the throw of the Scotch yoke 40 is approximately two feet.

The Scotch yoke 40 is secured to the upper and lower transfer bars 41and 42, respectively, and is carried vertically thereby. In turn, thebars 41 and 42 are carried r by pairs of corresponding trunnion rollers51 and 52 each secured to a vertically movable slide 53, and which spacethe bars.

The slides 53 are mounted in guides 54 secured to the back side of thecorresponding posts 2 on the front of the machine. Each slide 53 issupported vertically by atrunnion roller 55 fastened to the slide androlling on a cam bar 56.

The cam bar 56 extends longitudinally of the machine generally parallelto bars 41 and 42 and is reciprocally supported for longitudinalmovement on rollers 57 carried in brackets 58 on the adjacent rail oflower track 6.

The cam bar'56 has spaced depressed notches 59 in the .top thereofcorresponding to the number and location of the slides 53, so that whenbar 56 is pushed to the right from the location shown in FIG. to that ofFIG. 6, the rollers 55 ride down the incline to the bottom of thecorresponding notches 59 and thereby let the slides 53 and the transferbars 41 and 42 drop to a lower predetermined level. When the cam bar 53is returned to the position of FIG. 5 the rollers 55 ride up the inclineto the top of the bar where they support the slides 53 and bars 41 and42 at a predetermined upper level. The upper transfer bar 41 has aplurality of spaced upwardly extending pins 60 which interlockindividually with the corresponding platen 7 on upper track 5 when thetransfer bars 41 and 42 are in their uppermost position determined bycam bar 56. 7

Similarly, lower transfer bar 42 has a plurality of spaced downwardlyextending pins 61 which interlock individually with the correspondingplatens 7 on lower track 6 when the transfer bars 41 and 42 are in theirlowermost position determined by cam bar 56.

When the upper pins 66 interlock with platens 7 on upper track 5,longitudinal movement of the transfer bars 41'and 42 in one direction bythe crank 59 and Scotch yoke 49 will advance the platens to the nextstation. During this advance of the platens on track 5, the lower pins61 are raised from interlocking contact with the platens 7 on track 6 sothat these platens are not'moved at that time. Instead, each platen 7 ontrack 6 is held stationary by a spring pressed detent 62 carried by alongitudinal bar 63 above the adjacent rail of lower track 6.

When the lower pins 61 interlock with platens 7 on lower track 6,longitudinal movement of the transfer bars 41 and 42 in the returndirection by crank 39 and Scotch yoke 46 willmove the empty lowerplatens in a return direction opposite to the direction of advance ofthe upper platens. During this. return movement of the lower platens,the upper pins 66 are free from interlock with the upper platens and thelatter are fixed at their corresponding stations by the shot pins 18 aspreviously explained.

Reciprocal movement of cam bar 56 is effected in timed relation to theoperation of the Scotch yoke. 49. For this purpose 'a rotary cam 64 issecured on cam shaft 31 to actuate clutch 3S and thereby determine thetime cycle for the forward and return movements of the Scotch yoke bycrank 39 and the periods of dwell therebetween, and a cam 65 is securedto cam shaft 31 to actuate the cam bar 56 in timed relation to theforward and return movements of the yoke 40 so that the bars 41 and 42are in their uppermost positions when the yoke is advancing forwardlyand in their lowermost positions when the yoke is returning. 4

Cam 64 actuates clutch member 45 by a pivotally mounted lever 66 havinga yoke 67 at its upper end with trunnion members (not shown) riding in acircumferential groove 68 in the shift member, and a cam follower 69 atits lower end riding on cam 64. loading of lever 66 as showndiagrammatically at 70 in FIG. 4 retains the follower 69 in contact withthe. 'cam 64 and biases shift member 45 into interlocking engage-Suitable spring .7 r o. a taneous performance of the assembly operationsat the selected corresponding stations and the advance of the platens 7on track 5 to the next station for each, With 7 between the portions 71and 72 and which determine a dwell in the reciprocal movement of bars 41and 42 to allow time for assembly work on the upper platens and forraising and lowering of the transfer bars 41 and 42 by cam bar 56.

The cam 65 reciprocates cam bar 56 by means of a vertical slide 75supported on a cam follower 76 riding upon cam 65, and a bell cranklever 77 connecting the slide 75 with a pusher member 78 adjacent cambar 56.

The pusher member 78 is mounted to slide on red 79 which is secured atits ends to side brackets and 81 on cam bar 56.. Member 78 is normallyheld against bracket 85! by a strong spring 82 disposed between themember 73 and bracket 81. The spring 82 yields in an emergency in theevent a jamming of the machine should prevent actuation of the cam bar56 when follower 76 is raised by cam 65.

FIGS. 5 and 6 illustrate the actuation of the cam bar 56 by cam 65 withthe'parts shown in the opposite extremes of position. In the positionshown in FIG. 5 the slide '75 is down, the bar 56 is to the left and thetransfer bars 41 and 42 are raised for forward advance of platens 7.onupper track 5. 1n the position shown in FIG. 6 the slide 75 is raisedby cam 65, the bar 56 is to the right and the transfer bars 41 and 42are lowered for return movement of platens '7 on lower track 6. V

The cam 65 operates to lift slide 75 to move the cam bar '56 in adirection which permits rollers55 to ride down on the cam bar intonotches 59 and thereby lower transfer bars 41 and 42' by gravity. Thusthe cam 65 is not used against any substantial working force.-

For the purpose of raising transfer bars 41 and 42,

a power cylinder 83 has its output connected to bell crank lever 77 andis disposed to actuate the same to shift the cam bar 56 from theposition shown in FIG. 6 to that shown in FIG. 5 as the cam 65 dropsaway from and con-.

trols the downward movement of follower 76. During this movement, thepusher member 78 bears against bracket 8% to shift the cam bar 56 to theleft as described.

When the platens 7 on upper track S isuccesiv'ely reach device dd-whichturns the platen upside down and lowers it to a position of registrywith the end of lower track 6;

When the empty platens 7 have returned along track 6 i to the oppositeend, they move onto a turover device 85 which turns the successiveplaten-s right side up and elevates the same to alignment with track'5.The platen in each instance is then ready for intermittent advancemen-ton track 5 along the assembly line.

Turnover device 34 is driven from cam shafts-1 and turnover device 85 isdriven from cam shaft 4. The two turnover devices areconstructed alikeand therefore only turnover device 84 is illustrated in FIGS. 810,10.

Each turnover device 84 and 85 comprises a hub 86 fixed on a centralrotary shaft 87 parallel to tracks 5 and 6, and having four radial arms'88 disposed 90 apart around the circumference and carrying'four sets oftracks 89, 5t), 91 and 92 between the corresponding adjacent arms. 1 V

The tracks 69 and91 are diametrically spaced apart the distance betweentracks 5 and 6 so that when track 89 registers with the end of uppertrack 5 the track 9 1 registers with the end of lower track 6. At thistimetracks 99 and'92 are disposed vertically on opposite sides of theturnover device.

When the turnover device is rotated 90 in the direc tion of the arrow inFIGS. 8 and 9, track 90 will register with the upper track and track 92will register with the lower track 6. The tracks '89 and 91 are thendisposed vertically on opposite sides of the turnover device.

As each track 89-92 of the turnover device 84 successively registerswith the upper track 5 it is adapted to receive an empty platen 7therefrom, and as each track 89-92 of the turnover device successivelyregisters with the track 6 it is adapted to deliver an empty platen 7thereto. For this purpose transfer bars 41 and 42 move into the turnoverdevice 84 when advancing platens on track 5 and bars 41 and 42 move outof the turnover device When returning empty platens to track 6.

With respect to turnover device 85, transfer bars 41 and 42 move intothe device to deliver a return platen from track 6 to one of thecorresponding lower turnover tracks registering therewith, and bars 41and 42 move out of the turnover device to deliver an empty platen totrack 5.

Actuation of turnover device 84 is effected by two cams 93 and 94 on camshaft 31. Similar cams, not shown, are provided on camshaft 4 to actuateturnover device 85.

A follower 95 riding on cam 93 is carried by an arm 96 pivoted at oneend to the base 1. Arm 96 pivotally carries an upstanding rack 97 .atits opposite end and which meshes with a gear 98 driving a gear 99 onshaft 87 :to drive the turnover.

A fluid pressure cylinder 100 presses downwardly upon arm 96 to maintainfollower 95 biased toward contact with cam 93 at all times.

In operation cam 93 has a raised portion by which the rack 97 is held inits uppermost position meshing with gear 98. When cam 93 rotates towithdraw the raised portion from beneath follower 95, the cylinder 100will force arm downwardly from its position in FIG. 8 to its position inFIG. 9 and thereby move rack 97 downwardly and turn gear 98 in aclockwise direction to drive the turnover device counterclockwisethrough 90 of rotary movement.

This will carry the platen 7 on track 89 rotationally to the left 90 andpresent track 90 in registry with track 5 to receive the next platen 7therefrom. At the same time, track 92 which contains a platen 7 will bemoved into registry with lower track 6 for delivery of the platenthereto.

Oam 94 actuates mechanism to lock the turnover device against rotationbetween intermittent downward movements of rack 97. For this purpose afollower 101 rides upon cam 94 and is carried by an arm 102 pivoted atone end to base 1.

Arm '102-pivotally carries an upstanding push rod 103 which has asubstantially horizontal lever 104 impaled thereon and extending beneathgear 99 with its opposite end pivoted at 105 to base 1. A coil spring106 errcircling rod 103 biases lever 104 upwardly against the stop nuts107 threaded upon the upper end of rod 103.

Lever 104 carries a short rack 108 directly beneath gear 99 on shaft 87and which is adapted to be raised into mesh with gear 99 to lock theturnover device against rotation during loading and unloading of thedevice. Racks 97 and 108 function alternately in general so-that theturnover device is always controlled by one or the other.

Arm 102 also pivotally carries a link 109 extending upwardly to asubstantially horizontal lever arm 110 pivoted at one end to base 1 andpivotally carrying a T slot guide member 111 for rack 97.

When arm 102 is raised by cam 94, it first engages rack 108 with gear 99and then pivots arm 110 upwardly to raise guide member 111 and move thesame to the right by reason of the fixed pivot for the right hand end oflever arm 110, as shown in FIG. 9, thereby pulling rack 97 out of meshwith gear 98. For this purpose link 109 has a lost motion preferably inthe form of a slot 112 in the link receiving the pin '113 carried by arm110, so that it does not commence to raise arm 110 until after rack 108has meshed with gear 99. At this time cam 93 has already lowered rack 97to its lowermost position.

After rack 97 is withdrawn from gear 98 by guide member 111, the cam 93lifts follower against cylinder and the rack 97 moves upwardly to itsuppermost posit-ion as shown in FIG. 8, ready for the next cycle.

Then cam 94 lowers follower 101 which in turn pulls rack 108 out of meshwith gear 99 leaving the turnover device held against rotation by rack97 until cam 94 again lifts rack 108. For this purpose the lost motionslot 112 for link 109 also drops arm and engages rack 97 with gear 98before rack 108 drops downwardly from gear 99.

During turnover, the platens 7 are held on the corresponding tracks89-92 by means of a spring pressed cam latch. 114 carried by each trackand which engages the top of one of the trunnion rollers 8 supportingthe platen as shown :in FIG. 11.

The turnover devices are constructed with tracks 89-92 open at the outerend so that any platen thereon can be manually removed from the end ofthe track and replaced at any time.

The turnover devices are intermittently rotated during periods of dwellfor transfer bars 41 and 42, and when assembly operations are beingperformed at the. several stations.

In the event that inertia problems arise from backlash in the turnoverdrive, it may be desirable to employ a constant light drag as by somefriction device, not shown, applied to the shaft 87 for the turnoverdevice,

Inertia problems in the transfer of the platens are avoided by employingthe Scotch yoke drive 40 and the zero backlash gearing between the twocam shafts 4 and 31 and the cross shaft 29.

The several cams 11, 6'4, 65, 93 and 94 are constructed in halves orsegments so that they can be readily secured to the corresponding shafts4 and 31 at the desired positions therealong.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. 1m a machine of the class described, a conveyor track, a series ofwork carrying platens disposed to be moved along said track,reciprocating drive means disposed parallel to said track, means adaptedto interlock said drive means with said platens only during onedirection of movement of the drive means to advance said platens alongsaid track step by step with periods of dwell between successiveadvancing movements, a rotat able crank having a throw corresponding tothe distance of each successive advancing movement of said platens, aScotch yoke associated with said crank and carried by said reciprocatingdrive means to actuate the latter in accordance with the rotation ofsaid crank, and means to rotate said crank.

2. The construction of claim 1 in which said last named means comprisesa constantly rotating drive shaft, a cam shaft driven continuously bysaid drive shaft, a clutch having its output shaft driving said crankand its input shaft driven by said drive shaft; and cam means on saidcam shaft and connected to said clutch to actuate the same to provide anextended dwell in the actuation of said Scotch yoke at an end of thestroke therefor.

3. The construction of claim 2 in which the speed of said clutch inputshaft is selectively adjustable within limits to vary the relative timeof advancement and dwell in the step by step advancement of saidplatens.

4. In a machine of the class described, a conveyor track, a series ofwork carrying fixtures disposed to be moved along said track,reciprocating drive means disof the rotation of said crank generally ata dead center position to control the period of dwell of said fixturesbetween advancing movements. 5. The construction of claim 4 in whichsaid last name means comprises a clutch which selectively stops therotation of said crank for a predetermined period at dead center. I

6. In a machine of the class described, a conveyor track having aplurality of stations therealong, a series of separate platens on saidtrack and adapted to be individually advancedtherealong to successivestations, a return conveyor track parallel to and beneath said firstconveyor track and adapted to return the platens from the discharge endof said first track to the starting end thereof, means at said dischargeend of said first track to a receive successive platens therefrom andtransfer the platens successively to said return track, said meansserving to invert said platens during such transfer, means at saidstarting end of said first track to receive successive platens andtransfer the same thereto from said return track and to invert saidplatens during such transfer, and releasable latch means on saidreceiving and transfer means disposed to retain said platens upon saidmeans during transfer.

7. The construction of claim 6 in which said means each comprise arotatable turnover device With its axis parallel to said tracks andhaving diametrically opposed tracks spaced apart to registercorrespondingly with the adjacent ends of said first track and saidreturn track, and means to rotate said devices in correlation to theadvancement of said platens on said first track and while said platensdwell at the corresponding stations.

8. In a machine of the class described, a conveyor track having aplurality of stations therealong, a series of platens on said track andadapted to be individually advanced therealong to successive stations, areturn conveyor track parallel to said first conveyor track and spacedbeneath the same, a series of platens on said return track, means at thedischarge end of said first track to transfer successive platenstherefrom to said return track, means at the starting end of said firsttrack to transfer successive platens thereto from saidreturn track, a reciprocating drive member disposed between said track and movable inopposite directions parallel thereto, said drive member having meansthereon for interlocking with the platens on said first track when saidmember is moved in platen advance direction and having means thereon forinterlocking with the platens on said return track when said member ismoved in the platen return direction, and means to reciprocate saiddrive member.

9. The construction of claim 8 in which said reciprocating drive memberis supported for vertical shifting of the same upwardly to efiect saidinterlocking with the platens on said first track and downwardly toeffect said interlocking with said return platens, and means areprovided to shift said member up and down in correlation to thereciprocation thereof. i

10. The construction of claim 9 in which said last named means comprisesa cam bar extending longitudinally of said drive member, meanssupporting said reciprocating drive member upon said cam bar, cam meanson said cam bar engageable by said supporting means to raise and lowersaid drive member upon predetermined longitudinal reciprocation of saidcam bar, and means to longitudinally reciprocate said cambar.

11. In a machineof the class described, a machine bed of substantiallength, a conveyor-track supported thereon and having a plurality. ofwork stations therealong, a return track carried by said bed and spacedbeneath said conveyor track, a plurality of separate platens on saidtracks, means at the discharge end of said con veyor track. fortransferring successive platens therefrom to said return track, means atthe opposite end of said conveyor track for transferring successiveplatens thereto from said return track, a cam shaft extendinglongitudinally of said bed on each side thereof, cam means on one ofsaid cam shafts for driving said first named end transfer means, cammeans on the other of said cam shafts for driving said second endtransfer means, and a common drive for said cam shafts.

12. The construction of claim 11 in which said end transfer meanscomprise rotary turnover devices having tracks adapted to registeralternately with said conveyor track and said return track, and said cammeans eflects intermittent rotation of said'devices. V

13. In a machine of the class described, a machine bed of substantiallength, a conveyor track supported thereon and having a plurality ofwork stations theree along, a return track carried by said bed andspaced beneat h said conveyor track, a plurality of separate platens onsaid tracks, means at the dischargeend of said conveyor track fortransferring successive platens therefrom to said return tracks, meansat the opposite end of said conveyor track for transferring successiveplatens thereto from said return track, a cam shaft extendinglongitudinally of said bed on each side thereof, means on one side ofthe bed to advance successive platens on said conveyor track fromstation to station in step by step movement, means on the other side ofthe bed to index said platens at the corresponding stations betweensuccessive advance movements thereof, means operative from the cam shaftdisposed on the corresponding side of the machine to actuate said stepby step advancing means for said platens along said conveyor track,means operative from the other of said cam shafts and disopsed on thecorresponding side of the machine to actuate said platen indexing means,means to drive said end transfer means from said cam shafts, and acommon drive for said cam shafts.

14. In a machine of the class described, a machine bed of substantiallength, a conveyor track supported thereon and having a plurality ofwork stations therealong, a

return track carried by said bed and spaced beneath said conveyor trackand parallel thereto, a series of separate work platens on said tracks,reciprocating means disposed between said tracks and adapted to advancesuccessive platens in step by step movement from station to station onsaid conveyor track when said means moves in one direction and to returnsuccessive platens on' said return track when said means moves in theopposite direction, a cam shaft extending longitudinally of the bed oneach side of the machine, a cross shaft adjacent said cam shaft, powermeansto drive said cross shaft, speed reducing zero backlash gear driveconnections between said cross shaft and each of said cam shafts, rotarycrank means for driving said reciprocating means, means substantiallyfree of backlash for driving said crank means from said cross shaft,means operative from one of said series of separate platens on sm'dtrack and adapted to" be advanced in step by step movement from stationto station in succession, reciprocating means adjacent said track andadapted to advance all of said platens simul' taneously to the nextsuccessive station for each platen upon each forward movement of saidmeans, means to V drive said reciprocating means with acceleration and.deceleration of said reciprocating means effected by said means, anelectric motor drive for said means, and a zero blacklash speedreduction gear connecting said electric motor to said means to providemore uniform transmission of acceleration and deceleration forcesbetween said reciprocating means and said motor.

16. In a machine of the class described, a reciprocally driven membersubject to possible jamming in at least one direction of movement, acontinuously rotating cam drive member, a follower for said cam drivemember, a lever system interconnecting said follower and. said drivenmember to eiTect actuation of the latter in either direction under thecontrol of said cam drive member, means to yieldingly bias said drivenmember in one direction, means incorporated in said lever system toyield during actuation of said driven member in the opposite directionin the event of jamming, and power means to release said driven memberfrom actuation by said drive member.

, 17. In a machine of the class described, a reciprocally driven membersubject to possible jamming in at least one direction of movement, acontinuously rotating cam drive member, a lever system including a camfollower interconnecting said members to efiect actuation of said 1.2driven member in said one direction by said drive member, means toactuate said driven member in said other direction under the control ofsaid drive member, means incorporated in said lever system to yieldduring said actuation in the event of jamming, and power means torelease said driven member from said drive member.

18. The construction of claim 17 in which said last two means comprisein common a double acting fluid pressure cylinder and piston normallyretained in power transmitting relation to eiiect actuation of saiddriven memher in said one direction.

19. The construction of claim 14 in which said first named means isyieldable under predetermined actuating forces.

References Cited by the Examiner UNITED STATES PATENTS 1,020,133 3/12Dodds 21452 X 2,681,136 6/54 Ipsen.

2,861,672 11/58 Buhrer et a1. 198-85 2,881,711 4/59 Davis et al. 104-1283,013,506 12/61 Chill et a1. 104162 EUGENE G. BOTZ, Primary Examiner.

LEO QUACKENBUSH, Examiner.

1. IN A MACHINE OF THE CLASS DESCRIBED, A CONVEYOR TRACK, A SERIES OFWORK CARRING PLATENS DISPOSED TO BE MOVED ALONG SAID TRACK,RECIPROCATING DRIVE MEANS DISPOSED PARALLEL TO SAID TRACK, MEANS ADAPTEDTO INTERLOCK SAID DRIVE MEANS WITH SAID PLATENS ONLY DURING ONEDIRECTION OF MOVEMENT OF THE DRIVE MEANS TO ADVANCE SAID PLATENS ALONGSAID TRACK STEP BY STEP WITH PERIODS OF DWELL BETWEEN SUCCESSIVEADVANCING MOVEMENTS, A ROTATABLE CRANK HAVING A THROW CORRESPONDING TOTHE DISTANCE OF EACH SUCCESSIVE ADVANCING MOVEMENT OF SAID PLATENS, ASCOTCH YOKE ASSOCIATED WITH SAID CRANK AND CARRIED BY SAID RECIPROCATINGDRIVE MEANS TO ACTUATE THE LATTER IS ACCORDANCE WITH THE ROTATION OFSAID CRANK, AND MEANS TO ROTATE SAID CRANK.